Anyone who damages someone else's property should be made to restore it back to its pre-damage condition, regardless of how difficult or how long that would take. Even this burned out Panda. That way they might appreciate the time, effort and money that has been invested in said item (car in this case), and just how shit it is to have a car stolen and burned out.
This. Letting the knobbers run through the meadows wearing 'I repent' T-shirts isn't going to help much.